The invention is based on a dust and chip removal device, with a dust and chip retaining device.
The use of power tools to draw off dust and chips from a working surface using a suction device and moving it through a transport channel into a storage container, e.g., into cloth dust bags or paper filters, is known.
To prevent the dust and chips from flowing back out of the storage container when the power tool is switched off, it is known to provide a dust and chip retaining device that comprises a manually operated retaining flap. An operator can manually close and open the storage container via the retaining flap.
A dust and chip removal device having a transport channel for a cutting hand power tool forming the general class is made known in U.S. Pat. No. 6,047,693. The transport channel is formed by a first tube sectionxe2x80x94a xe2x80x9ctube connectorxe2x80x9dxe2x80x94secured to the hand power tool and by a second tube action secured to a dust bag.
The tube connector is equipped with a check valve inside that is located in a center section of the tube connector. The check valve comprises a cylindrical main body and a elastic poppet valve. The poppet valve is opened by compressed air generated by the dust suction fan, and it closes when the dust suction fan is switched off.
The invention is based on a dust and chip removal device, in particular for sanding hand power tools, having a transport channel, via which the dust and chips can be directed into a storage container secured to the hand power tool in particular, and having a dust and chip retaining device that comprises a retaining element to prevent the dust and chips from flowing back out of the storage container.
It is proposed that the retaining element comprises at least one passage that is closed by means of a holding force of an elastic element, and the passage opens automatically against the holding force starting at a certain delivery pressure, and the elastic element automatically closes the passage below a certain delivery pressure. Backflow of the dust and chips when the machine is switched off, and having the storage container accidentally closed during operation of the machine can be reliably prevented.
The holding force can be produced by means of a separate spring element, but the retaining element is advantageously made of a soft-elastic material, and the retaining element and the elastic element are designed as a single component, by way of which additional components, installation space, weight, assembly expense and costs can be spared.
If a channel has cross-sectional area that tapers toward the passage, and/or if the channel is designed in the shape of a nozzle, an advantageous opening behavior can be obtained with just a small amount of delivery pressure, and an increased particulate speed can be obtained in the region of the passage, by way of which a cleaning of the storage container in an anterior part closest to the passage and an advantageous filling of the storage container from the rear in the direction of the passage can be obtained.
The channel could basically be formed by a part of the machine or a part of the storage container. If the channel is formed by the retaining element, however, said retaining element can be used advantageously with a plurality of storage containers that can be produced cost-effectively, e.g., storage containers made of paper, and/or they can be used with multiple machines. With a channel formed by the retaining element and extending into the storage container, it can be further achieved that the weight of the dust and/or chips assists the elastic element in closing the passage when the machine is switched off and prevents the dust and/or chips from flowing back. This is accomplished in that the dust and/or chips act on the possibly elastically designed walls of the channel in the closing direction when the machine is switched off.
Instead of channel walls extending in the transport direction and toward each other toward the center, the tapering can also be produced advantageously by means of a protrusion extending against the transport direction. A reduction of the volume of the storage container caused by the tapering channel can be prevented, and a large volume in the storage container can be obtained.
In a further embodiment of the invention it is proposed that at least one wall of the tapering channel extends along an exponential function in the transport direction, by way of which advantageous flow conditions and an advantageous opening behavior can be obtained even when a small amount of delivery pressure is applied. Moreover, when the wall thickness of the retaining element decreases as it nears the passage, e.g., advantageously according to an exponential function, this has an advantageous effect on the opening behavior, especially when delivery pressures are low.
The passage can be formed by various embodiments appearing reasonable to one skilled in the art, e.g., by one or more incisions in a soft-elastic wall of the retaining element. If the passage is formed by at least two intersecting incisions, a large passage opening can be obtained in simple fashion.
It is further proposed that at least one seal and/or a support piece is integrally molded on the retaining element, by way of which additional components, weight and assembly expense can be spared.
The means of attaining the object according to the invention can be used with various devices appearing reasonable to one skilled in the art, but particularly advantageously with sanding hand power tools, such as hand-guided oscillating sanders, disk-type sanders, etc., with which fine chips and/or sanding dust are produced. Sanding dust and/or fine chips can be accelerated particularly advantageously via the nozzle-shaped channel and directed through the passage into a rear section of the storage container. Moreover, the means of attaining the solution according to the invention are used particularly advantageously with storage containers secured to the hand power tool that are moved into various positions with the hand power tool, and even into positions in which the dust and chips would flow back into the hand power tool out of the storage container when the hand power tool is switched off.